Device and method for encoding, decoding speech and audio signal

• US 20070078651A1
• Filed: 09/27/2006
• Published: 04/05/2007
• Est. Priority Date: 09/29/2005
• Status: Abandoned Application

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Kim, Miyoung, Lee, Shihwa, Kim, Dohyung, Kim, Sangwook
• Application Number:
  US11/527,550
• Publication Number:
  US 20070078651A1
• Time in Patent Office: Days
• US Class Current: 704/229
• CPC Class Codes: G10L 19/0204 using subband decomposition
• CPC Class Codes: G10L 19/20 using sound class specific coding, hybrid encoders or object based coding

Abstract

A device and method for encoding/decoding a speech signal and an audio signal. The device for encoding the speech signal and the audio signal includes a speech encoding unit which speech-encodes an input signal; an speech decoding unit which speech-decodes the speech-encoded signal; and an audio encoding unit which divides a difference signal between the speech-decoded signal and the input signal into a low band and a high band, allocates the number of bits to the divided bands, and audio-encodes the difference signal.

Claims

1. A device for encoding a speech signal and a non-speech audio signal, comprising:

a speech encoding unit which speech-encodes an input signal;

an speech decoding unit which speech-decodes the speech-encoded signal; and

an audio encoding unit which divides a difference signal between the speech-decoded signal and the input signal into a low band and a high band, allocates the number of bits to the divided bands, and audio-encodes the difference signal.

2. The device of claim 1, wherein the audio encoding unit comprises:

a sub-band analysis filter which converts the difference signal into a predetermined number of signals having sub-bands in a frequency domain;

a psychoacoustic model unit which calculates masking thresholds of the sub-bands of the converted signals;

a bit number allocating unit which groups the converted signals into the low band and the high band and allocates a low-band bit number and a high-band bit number to the low band and the high band, respectively;

a quantizing unit which quantizes the converted signals according to the low-band bit number and the high-band bit number; and

an entropy encoding unit which encodes the quantized signals.

3. The device of claim 2, wherein the bit number allocating unit calculates the low-band bit number using the following equation

B_LB=B_T×

T_LB/(T_LB+T_HB), and

wherein, B_LB denotes the low-band bit number, B_T denotes a total bit number allocated to the entire band, T_LB denotes an average value of the masking thresholds of the sub-bands included in the low band, and T_HB denotes an average value of the masking thresholds of the sub-bands included in the high band.

4. The device of claim 3, wherein the bit number allocating unit allocates the number of bits to the sub-bands included in the low band in the range of the low-band bit number using corresponding thresholds.

5. The device of claim 2, wherein the bit number allocating unit calculates the high-band bit number using the following equation

B_HB=B_T×

T_HB/(T_LB+T_HB), and

wherein, B_HB denotes the high-band bit number, B_T denotes a total bit number allocated to the entire band, T_LB denotes an average value of the masking thresholds of the sub-bands included in the low band, and T_HB denotes an average value of the masking thresholds of the sub-bands included in the high band.

6. The device of claim 5, wherein the bit number allocating unit allocates the number of bits to the sub-bands included in the high band in the range of the high-band bit number using corresponding thresholds.

7. A device for decoding a speech signal and a non-speech audio signal, comprising:

an audio decoding unit which audio-decodes audio-encoded signals to which the number of bits are allocated according to a low band and high band; and

a speech decoding unit which speech-decodes a speech-encoded signal.

8. The device of claim 7, wherein the audio decoding unit comprises:

an entropy decoding unit which decodes the audio-encoded signal;

an inverse quantizing unit which inversely quantizes the decoded audio signal according to a low-band bit number allocated to the low band and a high-band bit number allocated to the high band; and

a sub-band synthesis filter which converts the inversely quantized audio signal into an audio signal of a time domain.

9. A method of encoding a speech signal and a non-speech audio signal, comprising:

speech-encoding an input signal;

speech-decoding the speech-encoded signal; and

dividing a difference signal between the speech-decoded signal and the input signal into a low band and a high band, allocating the number of bits to the divided bands, respectively, and audio-encoding the difference signal.

10. The method of claim 9, wherein the dividing of the difference signal comprises:

converting the difference signal into a predetermined number of signals having sub-bands in the frequency domain;

calculating masking thresholds of the sub-bands of the converted signals;

grouping the converted signals into the low band and the high band and allocating a low-band bit number and a high-band bit number to the low band and the high band, respectively;

quantizing the converted signals according to the low-band bit number and the high-band bit number; and

encoding the quantized signals.

11. The method of claim 10, wherein the low-band bit number is calculated using the following equation

B_LB=B_T×

T_LB/(T_LB+T_HB), and

wherein, B_LB denotes the low-band bit number, B_T denotes a total bit number allocated to the entire band, T_LB denotes an average value of the masking thresholds of the sub-bands included in the low band, and T_HB denotes an average value of the masking thresholds of the sub-bands included in the high band.

12. The method of claim 11, wherein, in the grouping of the converted signals, the bit number are allocated to the sub-bands included in the low band in the range of the low-band bit number using corresponding thresholds.

13. The method of claim 10, wherein the high-band bit number is calculated using the following equation

B_HB=B_T×

T_HB/(T_LB+T_HB), and

wherein, B_HB denotes the high-band bit number, B_T denotes a total bit number allocated to the entire band, T_LB denotes an average value of the masking thresholds of the sub-bands included in the low band, and T_HB denotes an average value of the masking thresholds of the sub-bands included in the high band.

14. The method of claim 13, wherein, in the grouping of the converted signals, the number of bits are allocated to the sub-bands included in the high band in the range of the high-band bit number using corresponding thresholds.

15. A computer-readable medium having embodied thereon a computer program for performing the method of claim 9.

16. A method of decoding a speech signal and a non-speech audio signal, comprising:

audio-decoding audio-encoded signals to which the number of bits are allocated according to a low band and high band; and

speech-decoding a speech-encoded signal.

17. The method of claim 16, wherein the audio-decoding of the audio-encoded signals comprises:

decoding the audio-encoded signals;

inversely quantizing the decoded audio signals according to a low-band bit number allocated to a low band and a high-band bit number allocated to a high band; and

converting the inversely quantized audio signals into an audio signal of a time domain.

18. A computer-readable medium having embodied thereon a computer program for performing the method of claim 16.

19. A device for encoding a speech signal and a non-speech audio signal, comprising:

an audio encoding unit which divides a difference signal between an input signal and a speech-decoded signal into a low band and a high band, allocates the number of bits to the divided bands, and audio-encodes the difference signal,

wherein the speech-decoded signal is a decoded speech-encoded signal, and the speech-encoded signal is a speech-encoded version of the input signal.

20. The device of claim 19, wherein the audio encoding unit comprises:

a sub-band analysis filter which converts the difference signal into a predetermined number of signals having sub-bands in a frequency domain;

a psychoacoustic model unit which calculates masking thresholds of the sub-bands of the converted signals;

a bit number allocating unit which groups the converted signals into the low band and the high band and allocates a low-band bit number and a high-band bit number to the low band and the high band, respectively, the allocated band bit numbers being bit numbers for encoding the respective band signals;

a quantizing unit which quantizes the converted signals according to the low-band bit number and the high-band bit number; and

an entropy encoding unit which encodes the quantized signals.

21. The device of claim 20, wherein a masking thresholds are limit values which is usable to detect an original sound from a curve of an original sound and a minimum audible limit in psychoacoustic encoding.

22. The device of claim 20, wherein the average value of the masking thresholds of the sub-bands included in the low band is obtained by averaging the masking thresholds of the sub-bands included in the low band among masking thresholds calculated by the psychoacoustic model unit, and

wherein the average value of the masking thresholds of the sub-bands included in the high band is obtained by averaging the masking thresholds of the sub-bands included in the high band among the masking thresholds calculated by psychoacoustic model unit.

23. The device of claim 20, wherein the bit number allocating unit allocates a higher bit number to the high band than to the low band when the input signal is a speech signal, and allocates a higher bit number to the low band than to the high band when the input signal is a non-speech audio signal.

24. The device of claim 20, wherein the bit number allocating unit allocates the number of bits to the sub-bands using corresponding thresholds obtained by the psychoacoustic model unit.